1. Technical Field
The present invention relates to an image reading apparatus represented by a scanner.
2. Related Art
There are cases where a scanner, which is an example of an image reading apparatus, is provided on the upper portion of a recording apparatus, which is an example of a substructure, performing recording on a recording sheet. In this case, the scanner is provided to open and close the upper portion of the recording apparatus for maintenance of the recording apparatus. The opening and closing is frequently performed by a rotation operation of the scanner.
Further, a cover that opens and closes the scanner unit is provided at the upper portion of the scanner, and the cover is in many cases provided so as to open and close the scanner unit through a rotation operation. Alternatively, there are cases in which an automatic document transport device called an automatic document feeder (ADF) is provided on the upper portion of a scanner in place of such a cover; however, in many cases, the automatic document feeder is also provided so as to open and close the scanner unit by rotating.
Here, because the ADF in particular is heavy, there is concern of the ADF also opening due to momentum when the scanner is opened, and since the scanner is also heavy, there is concern of the apparatus falling over due to both being opened. In order to avoid such a problem, an apparatus configured such that in a case where one of the scanner and the cover or ADF is opened, the other is locked and both do not open at the same time has been proposed, as in JP-A-2006-42003, JP-A-2011-71820, and JP-A-2011-71929.
Here, the scanner is in many cases heavier than the cover or ADF on the upper portion thereof, and a comparatively strong force is necessary when opening the scanner. Therefore, a greater force acts more easily at a locking location that locks the scanner with respect to the substructure than the locking location that locks the cover or ADF with respect to the scanner.
However, since the locking mechanisms of any of JP-A-2006-42003, JP-A-2011-71820, and JP-A-2011-71929 have a configuration that locks the scanner with respect to the substructure using an arm (lever) that rotates, there is concern of the lock being released by the arm receiving force in the locking release direction due to a large force when the scanner in a locked state is to be opened, alternatively there is concern of the arm not withstanding a load and being damaged.